ULSD – Ultra Low Sulfur Diesel

Ultra Low Sulfur Diesel, also referred to as ULSD, is essentially diesel fuel which contains no more than 15 parts per million (ppm) sulfur. ULSD was required for use in most diesel fuel applications beginning in 2006, while diesel fuel containing higher levels of sulfur is being phased out. ULSD may be used in “on-road” or “off-road” applications, the difference being that “off-road” applications must be “red-dyed” in color so as to differentiate the